1. Field of the Invention
The present invention relates, in general, to surgical devices, specifically, to catheters or shunts for controlling the drainage of fluid between different areas of a human body and, more specifically, to catheters for draining cerebrospinal fluid from the cerebral ventricles to other areas of the body in the treatment of hydrocephalus.
2. Description of the Prior Art
Various types of shunts and catheters have been employed in surgical applications to control the flow of body fluids between various areas of a human body. Such shunts or catheters are extensively utilized in the treatment of hydrocephalus to overcome or control the lack of free circulation and/or absorption of cerebrospinal fluid within the brain.
In treating or controlling hydrocephalus, one end of a catheter is inserted through the skull into a cerebral ventricle of the brain, typically in a lateral ventricle of the brain. The opposite or outflow end of the catheter is attached to a valved shunt and directed either through the jugular vein toward the heart where the cerebrospinal fluid combines with blood or into the abdomino-peretoneal cavity where the cerebrospinal fluid is absorbed by the peritoneal fluid into the bloodstream.
The catheter is typically in the form of a hollow tube which is provided with a plurality of apertures at the ventricular or inflow end to permit the passage of fluids from the brain into the catheter and thence to the bloodstream of the patient. However, malfunctions frequently occur with such a catheter due to the blockage of the apertures in the inflow end of the catheter. Such blockage is usually caused by the migration of choroid plexus tissue within the ventricle over the apertures in the inflow end of the catheter. This tissue may block the apertures in the inflow end of the catheter in a relatively short period of time after the catheter has been inserted into the ventricle thereby rendering the catheter inoperative in relieving excess pressure due to the build-up of cerebrospinal fluid within the ventricle.
The likelihood of this type of catheter malfunction can be lessened by properly placing the inflow end of the catheter carrying the apertures sufficiently far anteriorally in the lateral ventricle of the brain such that the apertures are beyond the anterior extent of the choroid plexus. This prevents the migration of the choroid plexus over the apertures in the catheter.
In addition, the inflow end of the catheter should be positioned anterior to the foramen of Munro. However, it is difficult for the surgeon to accurately locate the tip end of the catheter the proper distance away from the chorioid plexus to prevent the migration of the choroid plexus over the inflow end of the catheter and yet still remain in the ventricle.
Various attempts have been made to correct this problem. U.S. Pat. No. 3,690,323 discloses a catheter having an umbrella-shape cover over the apertured end which is inserted into the brain in a closed position and opened by extending the ribs of the cover outward into the ventricle. A gauze-like material is attached to the ribs and is porous to cerebrospinal fluid flow so as to enable flow into the apertures and, yet, prevent the growth of choroid plexus over the apertures. However, growth of choroid plexus or other brain tissue over the ribs and gauze material eventually results in total blockage of the apertured end of the catheter.
U.S. Pat. Nos. 3,886,948 and 3,894,541 show a catheter having a plurality of spaced, radially extending flanges which are mounted on the inflow end of the catheter. The flanges surround the apertures formed in the inflow end of the catheter to prevent the growth of the choroid plexus growth over the apertures. The ribs are formed of a flexible material which bends during insertion through the dura and substance of the brain. However, blockage of the apertures can still eventually occur and, further, the surgeon is not provided with an adequate indication of the position of the tip end of the catheter during insertion of the tip end into the ventricle of the brain.
Thus, the above-listed exemplary catheters which are utilized to treat hydrocephalus lack any means for indicating an accurate positioning of the tip end of the catheter within the ventricle at a position to space the tip end of the catheter carrying the apertures from the choroid plexus to prevent the growth of choroid plexus over the apertures in the catheter.
As such, it would be desirable to provide a catheter which overcomes the problems of previously devised ventricular catheters which are emplaceable within a ventricle of a human brain to control the flow of excess fluids from the brain in the treatment of hydrocephalus. It would also be desirable to provide a ventricular catheter which provides an indication to the surgeon that the tip end carrying the apertures on the ventricular catheter is accurately positioned a pre-determined distance away yet still is located within the ventricle to lessen the likelihood of growth of choroid plexus tissue over the apertures in the tip end of the catheter.